PlayerEx

Level: this is permanent, and can be increased for experience levels.

└ +1 Skill Points

Skill Points: these can be spent on Constitution, Strength, Dexterity, Intelligence and Luckiness (you do not reduce your level by spending these).

Constitution
├ +1 Max Health
├ +1% Knockback Resistance (diminishing)

└ +1% Magic Resistance (diminishing)

Strength
├ +0.02/s Health Regeneration
├ +0.25 Melee Damage
├ +0.25 Armor (diminishing)

└ +1% Drowning Resistance

Dexterity
├ +0.1 Attack Speed (diminishing)
├ +0.25 Ranged Damage
├ +0.08 blocks/s Movement Speed (diminishing)
├ +5% Melee Critical Damage (diminishing)

└ +1% Falling Resistance (diminishing)

Intelligence
├ +2% Heal Amplification (diminishing)
├ +5% Ranged Critical Damage (diminishing)

├ +1% Fire Resistance (diminishing)
├ +5% Magic Amplification (diminishing)
└ +1% Wither Resistance (diminishing)

Luckiness
├ +0.2 Luck (vanilla luck)
├ +2% Melee Critical Chance (diminishing)
├ +2% Ranged Critical Chance (diminishing)
└ +2% Evasion (diminishing)

Max Health: the players maximum health (vanilla attribute).
Health Regeneration: the amount of health healed per second.
Heal Amplification: amplifies the amount of health restored when the player heals.
Armor: the players armor, reduces attack damage (vanilla attribute).
Armor Toughness: a measure of effectiveness of Armor (vanilla attribute).
Knockback Resistance: how much the player resists being knocked back (vanilla attribute).
Fire Resistance: reduces fire damage.
Falling Resistance: reduces falling damage.
Magic Resistance: reduces magic damage.
Wither Resistance: reduces wither damage.
Drowning Resistance: reduces drowning damage.
Movement Speed: how many blocks per second the player moves (vanilla attribute).
Melee Damage: the players attack damage (vanilla attribute).
Melee Critical Damage: attack damage multiplier.
Melee Critical Chance: the chance to Crit on a melee attack.
Attack Speed: how many fully charged attacks a player can launch per unit time (vanilla attribute).
Evasion: chance to completely dodge projectiles, both effect and damage.
Ranged Damage: the amount of damage added to arrows fired by a bow.
Ranged Critical Damage: arrow damage multiplier.
Ranged Critical Chance: the chance for the arrow to crit.
Lifesteal: the percentage of damage dealt that is healed.
Luck: the player's luck stat (vanilla attribute).
Reach Distance: how far away the player can interact with the world (reach-entity-attribute).
Attack Range: how far away the player can melee attack (reach-entity-attribute)
Step height: how many blocks the player can step over without jumping (step-height-entity-attribute)
Magic Amplification: amplifies most magic damage dealt (including some potions)

Level, Constitution, Strength, Dexterity, Intelligence and Luckiness all influence other attributes when they are levelled up.

+Syncs all player attributes to the client.
+The player heals (or damages if it is a negative value) the amount Health Regen / 20 every tick.
+The player can spend vanilla experience to level up, thereby gaining skill points. The amount of experience levels required to level up is configurable and depends on an exponential formula (the higher levelled you are, the more experience required to get to the next level).
+When the player heals, the amount of health healed is increased by Heal Amplification.
*Crits are now fully random (not jump-based), but the chance to crit is based on Melee Critical Chance.
*The damage crits do is no longer 1.5x, but based on Melee Critical Damage.
+All resistances reduces their respective damage inputs.
+The player heals a percentage of damage dealt, based on Lifesteal.
*Arrows no longer crit based on draw/angle: arrows crit based on Ranged Critical Chance, and the crit is no longer 2.0x, but based on Ranged Critical Damage.
+Evasion is a chance to completely block an arrow projectile.
+Most magic damage done by the player on a living entity is amplified by the Magic Amplification attribute.

+Added a button to the top right most corner of the survival inventory (the position is configurable). When clicked switches to the Player Attributes Screen.
+Added Player Attributes Screen. The player Attributes Screen has two tabs by default: the first tab displays general attributes, as well as buttons that allow the player to level up and spend skill points on Constitution, Strength, Dexterity, Intelligence and Luckiness. When hovering over an attribute, tooltips show more information including what that attribute does. The other tab displays combat attributes.
+When first gaining enough experience to level up, you make a particle cloud and a little sound plays – this is configurable.
+When skilling attributes, a little sound plays – this is configurable.
+When on multiplayer, every player displays their current level as a little nameplate below their name – this is configurable.

See the Images tab for examples.

+Can change the players starting attributes through datapacks, and/or modifying/adding/removing jsons. Configuring player attributes only needs to be done on the server, as those changes are synced to the client.

+Can fully customise all attributes, including their: default, minimum and maximum values; their names; and their functions (i.e. how much this attribute changes that attribute) – see the wiki for details.

+Can enable config option to reset all attributes on death (by default this is disabled).
+Can disable the level up particles/sound
+Can disable the skill attribute sound
+Can disable showing the "lvl" nameplate on multiplayer.
+Can move the attribute button position in the survival inventory.

+Can modify the amount of vanilla experience needed to level up initially, as well as the general levelling formula dictating how much experience is needed for the next level.

By default the levelling formula is: experience required for next level = 8 + offset + ((current level * multiplier / 100) – 2)^3

Where experience required for next level is a value from 0 to infinity that tells us how much experience we need to level up. The other parameter, current level, is just that – our current level; and the two remaining parameters are configurable and allow you to control the levelling curve: offset is how much experience we need to get the first level, while multiplier controls the steepness (difficulty) of the curve.

If you want to visualise the curve, plot it as: y = 8 + offset + ((x * multiplier / 100) – 2)^3

Where y is the amount of experience you need to get to your current level + 1, and x is your current level.

I cannot stress this enough, see the wiki for details on how to configure the player's attributes with datadriven development – i.e. datapacks. This is where the bulk of the configurability is.

All commands are sub-trees of "/playerex …"

/playerex reset <player>  -> Resets all the player's attributes to their defaults.
/playerex refund <amount> <player>  -> Lets the player refund the amount of skilled attributes for skill points.
/playerex refund <player>  -> The same as above but defaults to allow one refund.
/playerex levelup <amount> <player>  -> Gives the player <amount> levels.
/playerex levelup <player>  -> The same as above but only provides one level.
/playerex attribute <player> <attribute> get  -> Returns the total value of this attribute.
/playerex attribute <player> <attribute> set <amount>  -> Sets the attributes total value to <amount>.
/playerex attribute <player> <attribute> add <amount>  -> Adds <amount> to the attributes total value.
/playerex attribute <player> <attribute> modifier add <uuid> <name> <value> add|multiply|multiply_base  -> Applies a persistent attribute modifier to the attribute.
/playerex attribute <player> <attribute> modifier remove <uuid> <name> <value> add|multiply|multiply_base  -> Removes a persistent attribute modifier from the attribute.
/playerex attribute <player> <attribute> modifier value get <uuid>  -> Returns the value of the attribute modifier.

These commands should be used preferentially to the vanilla /attribute command when targeting players.